The most buzzed-about science findings of 2018 warned of a 'Hothouse Earth' and the dangers of alcohol. Here’s the full list.

In 2018 scientists published studies about a wide variety of new discoveries.

Their research uncovered new truths about what's best for human health, how we're affecting our planet, and the rise of fake news.

Here are the 10 most discussed scientific studies of the year - research that outraged, fascinated, frustrated, intrigued, delighted, and changed the world.

Scientific discovery can be a quiet enterprise.

A lot of scientific research happens in windowless laboratories, behind glowing computer screens, and out in remote fields and forests. But when scientists publish their work, they let the world in on what they've found.

A new scientific study can captivate the public imagination, stoke vibrant discussion, or even change public policy. Such was the case for a few of the most talked-about scientific findings of the year.

The following list of the top 10 science findings of 2018 comes from the data crunchers at Altmetric, who analysed how much various research papers got discussed on science blogs, social media, and in published news stories. They also took into account which studies were cited in Wikipedia entries and how many of them informed public policy.

The research in the resulting top 10 list looked into our diets, the planet's health, and even the way fake news spreads online. Here are the most influential and talked-about studies of 2018.

A team of public-health researchers interviewed 3,299 Puerto Rican households after Hurricane Maria pummelled the island. They discovered that the government's official death toll was far too low.

The team, led by researchers from the Harvard T.H. Chan School of Public Health, went house to house in remote and urban areas of Puerto Rico. They asked people if anyone at their home had died during - or as a result of - the hurricane.

Those surveys led the researchers to estimate that the true death toll from Maria on the island could be as low as 793 or as high as 8,498. Either way, that was far more than the death toll of 64 that the government had reported.

The research team, whose results were published in the New England Journal of Medicine, said at least a third of the deaths happened after the storm hit, since people couldn't get life-saving care amid the destruction.

Researchers from MIT tracked how fake news spreads online, and discovered that it moves a lot faster than the truth.

70news.wordpress.com

Surprise and disgust are both powerful emotions, and they're effective motivators when it comes to the spread of fake news and misinformation.

Researchers from MIT examined 126,000 Twitter posts, tweeted by 3.5 million users between 2006 and 2017. They found that a false post spreads to 1,500 new eyeballs six times as fast as the truth. Their results also showed that lies were 70% more likely to be retweeted, no matter how many followers the account had and regardless of whether it was verified.

They think there may be a simple reason why fake news is more appealing than the truth: It's shiny and new.

"We found that false news was more novel than true news, which suggests that people were more likely to share novel information," the researchers said. "Whereas false stories inspired fear, disgust, and surprise in replies, true stories inspired anticipation, sadness, joy, and trust."

A global study of drinkers in 195 countries suggested that no amount of alcohol is good for our health. But the results were not that simple.

The authors of a major study published in the Lancet found that, around the world, the more people drink, the more likely they are to develop cancer and the more likely they are to die.

The research caused a stir, since the authors suggested that there is no safe level of alcohol. Journalists around the world quickly picked up that headline and ran with it.

But there is some evidence that a moderate amount of booze (say, one drink per day) can help protect against some health conditions, notably heart disease and diabetes. The lead author of the Lancet study, Max Griswold from the University of Washington, said that doesn't matter because "combined health risks" associated with alcohol increase "with any amount of alcohol."

Others aren't so sure.

"Just because something is unhealthy in large amounts doesn't mean that we must completely abstain," Professor Aaron Carroll from Indiana University School of Medicine wrote for The New York Times after the study was published.

It's also important to remember that Griswold's finding wasn't based on entirely new research. Instead, his team reviewed nearly 600 previous studies on alcohol for a meta-analysis. Meta-analyses can make it hard to control for accuracy, since different researchers perform studies in dramatically different ways.

Plus, other unmeasured factors could also account for increases in deaths and health problems in drinkers. People who consume alcohol might be stressed, smoke, or have other underlying health issues or genetic differences that make them more likely to develop diseases.

"We could spend lifetimes arguing over where the line is for many people," Carroll wrote. "The truth is we just don't know."

In August, scientists predicted that we may be headed for a "Hothouse Earth" scenario in which the planet warms up rapidly, switching from self-cooling mode to self-warming.

"If this were to happen, the world would become far warmer than it's been for at least the past 1.2 million years," Business Insider's Kevin Loria wrote when the paper came out in Proceedings of the National Academy of Sciences in August. "Sea levels around the globe would likely rise between 10- and 91m higher than they are now."

The ripple effect of that warming would be felt around the globe. Permafrost that's trapping in greenhouse gases near the poles would thaw, the world's ice sheets would melt, and the Amazon rainforest (known as the "lungs of the planet") could die.

That's not just bad news for the plants and animals; it would also mean more flooded homes, stronger hurricanes, more intense wildfires, and dirtier air.

Luckily, the scientists behind this "Hothouse Earth" prediction believe there's still time to change course. In October, they authored a more hopeful report that suggested ways to avoid disaster.

Their suggestions involve major shifts in the ways we grow food and distribute money to cut down our greenhouse-gas emissions.

"The Earth's life-supporting systems are worth it," the authors wrote.

Scientists found even more evidence that exercise is an excellent way to boost your mental health. It doesn't matter much what kind of workout you do.

A study of 1.2 million US adults published in The Lancet Psychiatry reported, unsurprisingly, that people who exercised regularly tended to feel better.

In the study, researchers looked at national surveys from the Centres for Disease Control and found that people who said they exercised consistently reported fewer days when their mental health was "not good."

It didn't matter whether people were participating in team sports, going to the gym solo, cycling outdoors, going for a walk, or even doing some housework, the study authors found. Any type of exercise worked as long as people got moving three to five times per week, the researchers said.

Other studies suggest exercise can reduce stress, keep the heart healthy, protect against cognitive decline, and give you a better shot at avoiding an early death.

Scientists studied the diets of more than 447,000 people around the world, and may have zeroed in on the ideal dose of carbs for a long life.

Researchers analysed the diets of people in more than 20 countries, then compared that information to how long people lived.

They found that, in general, people who consumed a moderate amount of carbohydrates (about half a person's daily calories) and stuck to whole grains and unprocessed foods fared best. The results were published in The Lancet.

Lead researcher Sara Seidelmann, a cardiologist and nutrition researcher at Brigham and Women's Hospital in Boston, told Business Insider that a diet "rich in plant based whole foods such as vegetables, whole grains, legumes, and nuts is associated with healthy ageing."

Like the study on drinking, this research was a meta-analysis, which means we can't say for sure that the food is responsible for the longer lives. It may just be that people who consume roughly 50% of their daily calories from carbohydrates tend to live longer for other reasons like genetics or wealth that weren't measured by this study.

More randomised controlled trials would help us to know for sure.

We got new evidence that a big trash heap in the Pacific Ocean is collecting plastic at an astronomical rate.

The Ocean Cleanup

A study published in the journal Scientific Reports in March found that there may be more than 16 times as much plastic in the Great Pacific Garbage Patch than scientists previously thought.

The Ocean Cleanup Foundation visited the patch in 2015 with 18 vessels and used trawl nets to estimate how much plastic was in the area, which is more than 1.6 million square km wide. They reported the results of that work this spring.

The Great Pacific Garbage Patch isn't the only place where trash gets trapped in the ocean - there are at least four others like it scattered around the world. They're floating reminders of the impact that our plastic use has on oceans and sea life.

A study of 1,290 cancer patients found that those who opted for alternative cancer treatments were twice as likely to die.

For the study, researchers looked at cancer patients with early-stage breast, prostate, lung, or colorectal cancers. Some patients chose to use "complementary medicine," which can include herbs, supplements, acupuncture, special diets, and other treatments that haven't been clinically proven. Such treatments can help ease symptoms, but they haven't been shown to cure cancers.

The researchers found that patients who used the complementary treatments were more likely to either delay or refuse conventional treatments like chemotherapy, surgery, radiation, or hormone therapy. Those delays and refusals, in turn, led to higher death rates.

"Unfortunately, there is a great deal of confusion about the role of complementary therapies," lead study author doctor Skyler Johnson from Yale School of Medicine said in a release when the study was published in JAMA Oncology. "Although they may be used to support patients experiencing symptoms from cancer treatment, it looks as though they are either being marketed or understood to be effective cancer treatments."

Coral reefs are dying at alarming rates, and that has serious consequences for people.

"You like to breathe?" Michael Crosby, a marine scientist and the president of Mote Laboratory and Aquarium, asked Business Insider earlier this year. "Estimates are that up to 80% of the oxygen you are breathing in right now comes from the ocean. It doesn't come from the land. In order for you to continue to breathe, you have to have a healthy ocean."

Finally, humans received a reminder about how terribly insignificant we are, despite the tremendous impact we're having on the environment.

"A worldwide census of the total number of trees, as well as a comparison of actual and potential plant biomass, has suggested that the total plant biomass (and, by proxy, the total biomass on Earth) has declined approximately twofold relative to its value before the start of human civilisation," the study authors wrote.

In addition to killing off half of the world's plants, "humanity has caused the loss of 83% of all wild mammals," The Guardian reported when the study was released.

It's a reminder that the consequences of human activity now threaten most life on Earth.

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